Railway traffic controlling apparatus



Jan. 19, 1937. 1 c. G. HARWIG 2,068,331

RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Feb. 8, 19:55 I

I Fig.1. 7

'0 v 0 Y2 I? Y a Z k 12 a H G 0 FIB H6 120i 24 M r i' X PA! QF K XINVENTOR HIS ATTORNEY Patented Jan. 19, 1937 RAILWAY TRAFFIC CONTROLLINGAPPARATUS Carl G. Harwig, Wilkinsburg, Pa., assignor to The Union Switch& Signal Company, Swissvale, Pa., a corporation of PennsylvaniaApplication February 8, 1935, Serial No. 5,601

Claims.

My invention relates to railway traffic controlling apparatus, andparticularly to automatic signaling apparatus of the type involvinglight signals. More specifically, my invention relates to a means forproviding an additional indication on a light signal.

In the usual automatic block signaling system, the signals are spaced atthe maximum braking distance of the trains governed by such a system.The signals usually provide for three indications, namely, proceed,approach (prepare to stop at next signal) and stop. When it is desiredto increase the trafiic capacity of a railway equipped with such asystem, the signals necessarily have to be spaced less than brakingdistance so that the trains may follow each other more closely. Whenthis is done an additional indication has to be provided so that thespeed of the trains will be properly regulated upon approaching a stopsignal. One object of my invention is to provide a signal capable ofdisplaying four indications, and also to provide simple and reliablemeans for controlling each of the four indications. I shall term thefourth indication approach medium which indicates to an approachingtrain, approach next signal at not exceeding medium speed. Since thenext signal, as I shall explain hereinafter, will be displaying the"approach indication, the advancing train will pass such signal atmedium speed and, therefore, will be able to stop if the signal next inadvance is displaying a stop indication.

Other objects of my invention will become ap parent as the specificationprogresses.

I will describe two forms of railway trafiic controlling apparatusembodying my invention, and will then point out the novel featuresthereof in claims.

In the accompanying drawing, Fig. 1 is a diagrammatic view illustratingone form of railway trafiic controlling apparatus embodying myinvention. Fig. 2 is a diagrammatic View illustrating another form ofsuch apparatus also embodying my invention.

Similar reference characters refer to similar parts in each view.

Referring first to Fig. 1, the reference character Z designates astretch of railway track along which trafilc normally moves in thedirection indicated by the arrow. The rails I and IA of stretch Z aredivided, by means of insulated joints 2, into a plurality of successivetrack sections A-B, BC, 0-D, and D-E. Each such track section isprovided with a track circuit. Each such track circuit is provided witha source of current, here shown as a battery 3, connected across therails at the leaving end of the section, and with a track relaydesignated by the reference character T with a suitable distinguishingsufiix corresponding to the location and connected across the rails atthe entrance end of the section.

Located adjacent the entrance end of each section is a signal designatedby the reference character J with a distinguishing sufiix and here shownas a light signal comprising four units; namely, a green lamp G, a redlamp R, and two yellow lamps Y and Y2. When the green lamp G is lighted,the signal indicates proceed; when the yellow lamp Y is lighted, thesignal indicates approach medium, that is, approach next signal atmedium speed; when both yellow lamps Y and Y2 are lighted, the signalindicates approach, that is, prepare to stop at next signal; and whenthe red lamp R is lighted, the signal indicates stop.

It will be noted, when lamps Y and Y2 of a particular signal are bothlighted, that such lamps are connected in series and, therefore, asource of double voltage will be required to light these lamps. I haveprovided each signal with such a source which is here shown as anauto-transformer designated by the reference character P with a suitabledistinguishing suflix corresponding to the location. It is understood,of course, that any other source of increased voltage sufficient tolight two such lamps in series may be used instead of the transformer P,such, for example, as a battery having twice the number of cellsrequired for lighting one of the lamps.

It will also be apparent that, due to lamps Y and Y2 being connected inseries, neither lamp will be lighted if the other is burned out orotherwise defective, when trafiic conditions are such as to causedisplay of the approach indication. If lamps Y and Y2 were connected inmultiple, one of the yellow lamps could be lighted with the other burnedout which might cause the signal to display the approach mediumindication instead of the approach indication. My invention, therefore,prevents the display of a less restrictive indication in the event thatone of the yellow lamps should be defective.

I shall describe the circuits and operation for signal JA only sincesignals JB, JC, and JD are controlled and operated in a manner similarto that which will be described for signal JA.

The red lamp R is provided with a circuit which passes from terminal Xof a suitable source of alternating current, through back contact 4 oftrack relay TA and lamp R to terminal 0 of the same source of current.Thus, it will be seen that lamp R, will be lighted only when relay TAbecomes released, that is, when section AB is occupied.

The yellow lamp Y is provided with a circuit which passes from terminalX through back contact 5 of track relay TC, front contact 6 of trackrelay TB, front contact of track relay TA and lamp Y to terminal 0.Thus, lamp Y will be lighted only when section (3-1) is occupied andrelay TC becomes released provided section A-l3 and B0 is eachunoccupied.

The green lamp G is provided with a circuit which passes from terminal Xthrough front contact 8 of track relay TC, front contact 9 of trackrelay TB, front contact iii of track relay TA and lamp G to terminal 0.Lamp G, therefore, will be lighted only when sections AB, BC, and CD areall unoccupied and relays TA, TB and TC are all energized.

The yellow lamp Y2 in series with lamp Y is provided with a circuitwhich includes the secondary winding l! of auto-transformer PB and frontcontact 2 of track relay TA. The primary winding !3 of transformer PE isconnected to terminal 0 permanently, and to terminal X through backcontact Hi of track relay TB. Thus, it will be seen that primary l3.will become energized only when section B-C is occupied and relay TBbecomes released, and that when relay TB is released, lamps Y and Y2will each be lighted provided section AB is unoccupied.

From the foregoing description it is now apparent that signal JA willindicate successively stop, approach, approach medium and clear in rearof a train moving in the direction of the arrow and occupying sectionsAB, BC, CD, and D-E, respectively, in succession. Such train, therefore,will be fully protected against a following train.

Referring now to Fig. 2, the track Z has been divided into the usualtrack sections A-'-B, 13-0, and CD. Section B-C and CD is each providedwith a track circuit including a battery 3 and a track relay designatedby the reference character T with a suitable distinguishing sufiix.Section BC and CD is each also provided with a signal designated by thereference character H with a suitable distinguishing suffix. Each signalis here shown as a color light signal comprising three lamps, namely, agreen lamp G, a yellow lamp Y and a red lamp R.

Section AB, however, has been further divided by insulated joints 2 intosection AA! and A!B. The track relay TA is connected across the rails ofsection AA! and a track relay TAI is connected across the rails ofsection A!B, each such section being provided with. a track battery 3.The section A--B is provided with a signal I-IA which has a yellow lampY2, in addition to the usual green lamp G, yellow lamp Y, and red lampR.

Associated with track relay TA! is an autotransformer PA! which attimes, as will be explained hereinafter, is effective for energizing thetwo yellow lamps Y and Y2.

Since signals HB and HC are the usual three indication automatic signalscontrolled in the well-known manner, I will explain the control andoperation of signal HA only.

The red lamp R of signal HA is lighted only when track relay TA isreleased and back contact I5 of this relay becomes closed; therefore,signal I-IA displays the stop indication only when section AA! isoccupied by a train.

The two yellow lamps are connected in series by a circuit which includesfront contact !6 of track relay TA and secondary ll of theautotransformer PA!. The primary I8 of transformer PA! is energized onlywhen back contact IQ of track relay TA! becomes closed, that is, whensection A!B is occupied. Thus, the two yellow lamps Y and Y2 of signalI-IA are both lighted when section A!B is occupied and section AA! isunoccupied, so that a following train may occupy section AA!. I shallterm this indication a closing-in indication since it permits two trainsto occupy section A-B at the same time. Such an indication may be usedat points Where it is desired to facilitate and hasten the loading andunloading of passengers, such, for example, as at and near stationplatforms.

The yellow lamp Y is provided with a circuit comprising front contact 29of track relay TA, front contact 2! of track relay TA! and back contact22. of track relay TB. Thus, signal HA displays the usual approachindication only when relay TA and TA! is each energized and relay TB isdeenergizedthat is, when sections AA! and A!B are unoccupied and sectionB-C is occupied.

The green lamp G is lighted only when relay TA, TA! and TB is eachenergized and front contact 23, 24, and 25, respectively, is eachclosed; therefore, signal HA displays the proceed indication only whensection AAl, A!B, and B-C is each unoccupied.

From the foregoing description of the two forms of my inventionillustrated in Figs. 1 and 2, it will be seen that I have provided asimple 7 and reliable means for securing a fourth indication on a signalwhich indication may be employed in an .automatic block signaling systemfor regularly displaying a fourth indication at all signals of such asystem, or may be employed at special locations as a closing-in signal.My invention also provides a means for insuring that, in the event eachof the two yellow lamps do not become lighted, one yellow lamp may notbe lighted and cause the display of a misleading and less restrictiveindication. It will be noted that all relays employed in my inventionare track relays, therefore, my invention provides the four indications,hereinbefore described, without the use of line relays.

Although I have herein shown and described only two forms of apparatusembodying my invention, it is understood that various changes andmodifications may be made therein within the scope of the appendedclaims Without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a section of railway track, a signal for said.section comprising a red lamp and ayellow lamp as well as a green lamp,means for lighting said Ted lamp when one particular portion of saidsection is occupied by a train, means for lighting said yellow lamp whenonly a certain zone in advance of said section is occupied, means forlighting said green lamp when said section and such certain. advancezone are both unoccupied, another yellow lamp on said signal, and meansfor. lighting both of said yellow lamps when another particular portionof said section is occupied by a train and such one particular portionis unoccupied.

2; In combination, a stretch of railway track divided. into a pluralityof track sections, a plurality of signals one for each section each suchsignal comprising a red lamp and a green lamp as well as a pair ofyellow lamps, means for energizing the red lamp at each signal when aparticular section in advance of the associated signal is occupied by atrain, a series circuit for each pair of yellow lamps, means forenergizing each such circuit when only another particular section inadvance of the associated signal is occupied, means for energizing oneyellow lamp of each signal when only still another particular section inadvance of the associated signal is occupied, and means for energizingthe green lamp of each signal when each such section in advance of theassociated signal is unoccupied.

3. In combination, a stretch of railway track divided into three tracksections each such section having a track circuit including a. trackrelay, a signal for said stretch comprising a red lamp and two yellowlamps as Well as a green lamp, a source of current, a circuit connectingsaid source with said red lamp and including a back contact of the trackrelay of the first section in advance of said signal, a circuitconnecting both of said yellow lamps with said source and including afront contact of the track relay for the first section as well as a backcontact of the track relay for the second section in advance of saidsignal, a circuit connecting said source with one of said yellow lampsand including a front contact of the track relay for the first sectionas well as a front contact of the track relay for the second section anda back contact of the track relay for the third section, and a circuitfor said green lamp including a front contact of each such track relay.

4. In combination, a stretch of railway track divided into two sections,a first and a second track circuit each including a track relay for thefirst section and a third track circuit including a track relay for thesecond section, a signal for said stretch comprising a red lamp and twoyellow lamps as well as a green lamp, a circuit for said red lampincluding a back contact of the track relay for the first track circuit,a circuit for both of said yellow lamps including a front contact of thetrack relay for the first track circuit and a back contact of the trackrelay for the second track circuit, a circuit for one of said yellowlamps including a front contact of the track relay for the first trackcircuit and a front contact of the track relay for the second trackcircuit as well as a back contact of the track relay for the third trackcircuit, and a circuit for said green lamp including a front contact ofeach such track relay.

5. In combination, a forward section and a rear section as well as anintermediate section of railway track, a track circuit including a trackrelay for each section, a signal including a first lamp and a secondlamp, a transformer, a circuit for said first lamp including a backcontact of the track relay for the forward section as well as a frontcontact of each of the track relays for the intermediate and rearsections, and a circuit connecting said two lamps in series andincluding said transform-er as well as a back contact of the track relayfor the intermediate section and a front contact of the track relay forthe rear section.

CARL G. HARWIG.

